The present invention relates to a device for automatically weighing objects being conveyed, and more specifically to a device which permits automatic weighing of slender or piece-like objects being conveyed on a conveyer.
Traditionally, in order to weigh piece - like objects such as letters, it is necessary to manually place the object on a scale, such as electronic scale, and then remove it from the scale and affix a label or stamps according to the range in which the weight of the object falls. However, these procedures require increased manual labor which increases the overall cost of the operation. Moreover, these manual procedures are prone to errors, especially when the classification system for the ranges of weight is sophisticated.
Although prior art systems exist that convey an object to be weighed onto an electronic scale, the technical problem exists in isolating the object from contact with other objects to obtain an accurate measurement of weight.
Therefore, a problem yet to be solved in the prior art is how to separate a moving object to be weighed from the conveyer and, after weighing it, restoring the object onto the conveyer to keep the operation moving in a completely automatic manner.
In a prior art system a weighing plate of an electronic scale is urged up when the moving object to be weighed reaches a position above the electronic scale thereby separating the object from the conveyer. The weighing plate is restored to its original position after the weighing process. However, the electronic scale is a high precision device and this up-and-down movement adversely affects its precision and may be harmful to its construction. Thus an accurate and stable weighing result is difficult to obtain.
The present invention is a novel weighing device that overcomes the disadvantages of the prior art weighing devices for weighing a moving piece - like object.